Non-catalytic durable press process for treating cellulosic material using formaldehyde vapor and post-heating

ABSTRACT

The dimensional stability, wrinkle resistance, smooth drying characteristics and total shape retentivity of cellulosic material such as cotton fabrics are improved by impregnating the fabric with an aqueous solution of a monomeric compound which has at least one active hydrogen and reacts with formaldehyde, e.g., urea, exposing the impregnated fabric to an atmosphere containing formaldehyde vapors in the absence of a catalyst until a creaseproofing amount of an at least partially polymerized, substantially water-insoluble condensate (such as an amideformaldehyde condensate) is affixed to the fabric without, however, effecting any substantial amount of cross-linking with the cellulosic fiber. The thus-exposed fabric is thereafter postheated in an inert gaseous atmosphere also in the absence of a catalyst to further polymerize and cross-link the fabric.

United States Patent 1191 Gamarra et al.

[ NON-CATALYTIC DURABLE PRESS PROCESS FOR TREATING CELLULOSIC MATERIALUSING FORMALDEl-IYDE VAPOR AND POST-HEATING [75] lnventors: Jose P.Gamarra, San Jose; Ronald Swidler, Palo Alto, both of Calif.

[73] Assignee: Cotton, Incorporated, New York,

22 Filed: July 13, 1972 21 AppljNo; 271,237

- [52] US. Cl 8/182, 2/243, 8/115.7,

8/187, 8/189, 8/194, 8/DIG. 4, 8/D1G. 9,

' S/DIG. 10, 8/DIG. 21, 28/144 51 Int. Cl...l) 0 6m 13 14, ooe 13/40,D06 13/54 [58] Field ofSearch 38/144; 2/243;8/'116.4;8/182,184,185,186,187,189,194

[56] References Cited UNITED STATES PATENTS 3,545,913 12/1970 Joarder etal 8/116.4 3,653,805 4/1972 Gamarra et al.... 8/116.3 3,663,158 5/1972Brenner et al. 8/1 16.4

OTHER PUBLICATIONS Joarder et al., Textile Research Journal 37,

Joarder et al., Textile Research Journal, 39, 49-54 (1969). 4

1451 Apr. 2,1974' Chemical Abstracts, 58, 9268 Gagliardi et al., TextileResearch Journal, 36, l68-177 (1966).

Mehta et al., Journal of the Textile Institute, 58, 279-292 (1967).

Primary Examiner-George F; Lesmes Assistant Examiner-J. Cannon Attorney,Agent, or FirmBurns, Doane, Swecker Mathis [57] ABSTRACT fiber. Thethus-exposed fabric is thereafter postheated in an inert gaseousatmosphere also in the absence of a catalyst to further polymerize andcross-link the fabric. 1 1

9 Claims, No Drawings NON-CATALYTIC DURABLE PRESS IROCESS FOR TREATINGCELLULOSIC MATERIAL USING FORMALDEHYDE VAPOR AND POST-HEATING BACKGROUNDOF THE INVENTION In recent years, various methods have been devised fortreating cellulosic fiber-containing products such as cloth made ofcotton or cotton blends in order to impart durable wrinkle resistanceand smooth drying characteristics thereto. For example, cellulosicmaterials have been cross-linked with formaldehyde in the presence of anumber of various catalysts giving durable cross-links having goodresistance to repeated laundering and also to various acids and alkaliesand chlorine bleaches.

US. Pat. No. 3,653,805, for example, discloses impregnating thecellulosic material with a formaldehydereactive compound, such as ureaand then contacting the impregnated fabric with formaldehyde vapors toform an insoluble reaction product on the fabric in the to a gaseouscatalyst and cured to give a durable press product.

Indeed,'many of the prior art processes relating to durable pressproducts using formaldehyde or formaldehyde-reactive materials haveinvolved the use of acidic catalysts such as sulfur dioxide, formicacid, acetic acid, zinc chloride and the like. While these catalysts areeffective in causing cross-linking or curing of the materials, they maydegrade the physical properties of the cellulosic material.

The use of an uncatalyzed method for producing a durable press producthas been attempted in the prior art, but no commercially suitableprocess has heretofore been found insofar as extremely long reactiontimes, e.g., hours, were required to even approach acceptable minimumdurable press property levels. See, for example, An Uncatalyzed,Vapor-Phase Cross-linking Reaction of Cotton Cellulose withFormaldehyde, Joarder et al., Textile Research Journal, 39, No. 1, pp.49-54 (January, 1969).

Therefore, the search has continued for a relatively rapid non-catalyticprocess able to give rise to an improved balance between physicalproperties and durable press properties for cellulosic materials such ascotton fabric.

SUMMARY OF THE INVENTION Accordingly, a primary object of the presentinvention is to provide a noncatalytic durable press process fortreating fiber-containing cellulosic materials which processsubstantially prevents or alleviates the problems mentioned above.

A more specific object is to provide a non-catalytic process whichimparts an improved balance of durable press and physical properties tocellulosic materials.

Another specific object is to provide a non-catalytic durable pressprocess for use with cellulosic materials which produces improvedwrinkle resistance and smooth drying characteristics, keeps any loss oftensile strength and abrasion resistance to a minimum, and requiresrelatively short processing time.

These and other objects, as well as the scope, nature and utilization ofthe invention will become more clearly apparent from the following moredetailed description. Unless otherwise indicated, all proportions andpercentages of materials or compounds are expressed on a weight basisthroughout this specification and appended claims. 1

in accordance with the present invention, a noncatalytic process isprovided for improving the dimensional stability, wrinkle resistance,smooth-drying characteristics and total shape retentivity of acellulosic fiber-containing fabric which comprises: (a) applying to thecellulosic fiber-containing fabric a catalyst-free aqueous solution of amonomeric compound which has at least one active hydrogen and reactswith formaldehyde; (b) exposing the impregnated fabric to an atmospherecontaining formaldehyde vapors in the absence of a catalyst'until acreaseproofing amount of an at least partially polymerized condensate ofthe monomeric compound and formaldehyde in substantially water-insolubleform is affixed on said fabric without effecting any substantial amountof cross-linking with the cellulosic fiber; and (c) post-heating saidfabric in an inertgaseous atmosphere in the absence of a catalyst at atemperature of from about C. to about C. for from about 1 to about'20minutes to further polymerize and cross-link the fabric.

The essence of the present invention is the discovery that bypost-heating in the absence of a catalyst or formaldehyde a fabric whichhas been impregnated with a catalyst-free aqueous solution of amonomeric compound which has at least one active hydrogen and reactswith formaldehyde, such as urea, and then exposed to formaldehyde vapors(again in the absence of a catalyst), a substantially improved wrinkle'resistance and a significantly reduced overall processing time areachieved with only minimal degradation of physical properties.Heretofore it has been thought that a catalyst must be padded onto thefabric, either throughvan aqueous padding bathor by vapor padding, inorder to achieve acceptable durable press properties and processingtimes. The present invention has achieved these goals without addingthese catalysts to the system, thus avoiding sacrificing of significantlosses in physical properties of the material.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is usefulfor treating various natural or artificial cellulosic fibers alone or inmixtures with each other in various proportions or as mixtures withother fibers. Such natural cellulosic fibers useful herein include, forexample, cotton, linen, flax, hemp and jute. Useful regenerated orartificial cellulosic fibers include viscose rayon and cuprarnmoniumrayon. Other fibers which may be used in blends with one or more of theabove-mentioned cellulosic fibers are, for example, cellulose acetate,polyamides, polyesters, polyacrylonitrile, polyolefins, polyvinylchloride, polyvinylidine chloride and polyvinyl alcohol fibers. .Suchblends preferably include at least about 15 percent by weight and mostpreferably at least about 35 percent by weight of cotton or othercellulosic fibers.

A fabric may be knit, woven or non-woven, or be any otherwiseconstructed fabric. The fabric may be flat,

creased, pleated, hemmed or sewn or otherwise formed to produce anarticle such as a garment of any desired shape prior or subsequent tocontact with the reactive vapor phase containing formaldehyde. Afterprocessing,'the formed cross-linked fabric will maintain substantiallythe original configuration for the life of the article, that is, awash-wear or durable press fabric will be produced. I

In accordance with the present invention, the cotton orcellulose-containing fabric is impregnated with a catalyst-free aqueoussolution containing a monomeric compound which has at least one activehydrogen and reacts with formaldehyde, e.g., a compound of the amidetype.

Suitable amide-type, reactive with formaldehyde compounds are typicallywater-soluble and include various ureas such as urea, butyl urea,ethylene urea, cyclic propylene urea, allyl urea, cyclicdihydroxyethylene urea, cyanuramide (melamine), thiourea as well asformamide, acetamide, maloamide, acrylamide, the lower. alkyl (e.g., C Cor hydroxyalkyl carbamates, such as ethyl carbamate and-hydroxyl ethylcarbamate, aryl sulfonamides, such as benzene-sulfonamide orp-benzene-disulfonamide, the lower (e.g., C C alkyl sulfonamides orbis-sulfonamides such as methane-, ethane-, n-butaneorisobutane-sulfonamide, methylene-bis-methane-sulfonamide,ethylene-bismethane-sulfonamide, l,3-propane-bis-methane sulfonamide andso on. Urea and ethyleneurea are preferred.

It is particularly advantageous to impregnate the fabric with theaqueous solution of the amide compound was to produce adry add-on ofbetween about 0.5 and 25, preferably between about 2.5 and l5,,percentby weight of the fabric.

The amide compound is preferably applied in an aqueous solution whichmay havea pH of from about 4 to 12. Generally, the aqueous solution willhave an alkaline pH. Often, the pH will be between above about 7 andless than about ll, preferably between about 8 cent, preferably'fromabout 3 to about 20percent, most preferably from about to about 15,percent of theamide.

Pretreatment of the fabric; prior to the exposure to the formaldehydevapors, with polymeric resinous additives that form soft films such asconventional disperand 9, and containing from about 1 to about 25perpreferably from about 3 to about 65, most preferably from about 5 toabout 15, percent by weight of the dry cellulosic fabric material.

if desired, the impregnated fabric may be dried and then used in garmentmanufacture (e.g., cutting, sewing and pressing) either immediately orafter shipment to a different location or after storage of indefiniteduration. The resulting garments may then be further treated asdescribed hereinbelow either immediately or after storage of indefiniteduration. The impregnated fabric (or garment) is exposed in the absenceof a catalyst to an atmosphere containing formaldehyde vapors until acrease-proofing amount of an at least partially polymerized condensateof the monomeric compound and formaldehyde (e.g., a partiallypolymerized ureaformaldehyde condensate) in substantially waterinsolubleform is affixed on the fabric without, however, effecting anysubstantial amount of cross-linking with the cellulosic fiber.

Although there is no substantial cross-linking, there apparently may besome binding, such as grafting of the condensate onto hydroxyl groups ofthe cellulose, taking place during the formaldehyde vapor contact step.A crease-proofing amount of the at least partially polymerizedcondensate is that amount which, when the fabric is post-heated, yieldsa fabric having acceptable durablepress properties.

The atmosphere of the reaction zone may also contain air or any othernon-acidic and non-deleterious gas which does not react with theformaldehyde or the monomeric compound .and does not catalyze theirreaction. Often, the reaction zoneatmosphere contains from about 1 toabout 100, preferably about 30 to about 95, volume percent formaldehyde.

Contact of the impregnated fabric with the formaldehyde vapor-containingatmosphere can be performed at a temperature of from about 100C. toabout l60C.,

maldehyde vapor-containing atmosphere may be emsions or latices, canresult in unusually great incremental improvement in wrinkle recovery ofthe treated fabric. Polymer additives can also improve the flex,abrasion resistance, and tear strength, or alter the ratio of drywrinkle recovery to wet wrinkle recovery, or in some instances, shortenthe reaction time needed to produce an acceptable durable press fabric.Polymeric additives suitable for such purposes are, in most cases,available commercially in concentrated aqueous latex forms, and it isdesirable to dilute these to a concentration of about 1 to about 30,often from about 5 to about ployed. For example, a batch systemutilizing a closed vessel 'ortube containing the reactive vapor phaseatmospheremay be used into which the impregnated monomer-containingfabric may be placed and there exposed to the atmosphere for theappropriate time. In the alternative, a dynamic or continuous system canbe used such as one wherein a gas stream containing formaldehyde vaporis passed through a closed elongated chamber through which theimpregnated fabric or articles are also passed at an appropriate rateeither concurrently or countercurrently relative to the. gas. It is alsopossible to use combinations of the above, that is, such as by-passing astream containing formaldehyde vapors over a stationary fabric. 7

The required formaldehyde vapor may be generated in any convenientmanner, such as by heating a suspension of paraformaldehyde in mineraloil to generate formaldehyde gas which is then metered into the treatingchamber. The formaldehyde vapor will be present in the reaction zone inan amount at least sufficient to react with all of the amide compoundand generally will be present in an excess of that amount.

Typically, at the end of the formaldehyde vapor contacting step, thefabric is desirably heated at a temperature above about 80C., e.g., inthe range of from about 100C. to about 180C., preferably from about140C. to about 160C. for from about 1 to about 20 minutes, preferablyfrom about 3 to about minutes, to further polymerize and cross-link thefabric thus improving its durability to laundering as well as improvingthe durable press characteristics of the treated fabric. in addition,this post-heating step will volatilize and remove any water vapor,unbound formaldehyde and other volatile residues. This post-heating stepmay also allow a reduction in the time of exposure to the formaldehydevapor without sacrificing durable press performance. Heating thetreating fabric may advantageously be performed in any suitable fabricheating chamber.

The treated fabric may be subjected to the postheating step immediatelyafter being exposed to the formaldehyde vapors or it may be stored foran indefinite period of time. If desired, the fabric may be used ingarment manufacture after exposure to formaldehyde vapors and before thepost-heating step. The treated fabric is preferably not washed prior tothe post-heating step. Although we do not wish to be bound I bytheoretical considerations, it would appear that the least. partiallypolymerized condensate formed in the formaldehyde vapor contact step maycontain some re- 2 pounds, respectively).

active groups (such as methylol groups), the reactivity of which may bereduced by washing with water. The efficiency of the overall process isthus considerably reduced when the fabric is washed between these steps.

. The invention is additionally illustrated in connection with thefollowing examples which are to be considered as illustrative of thepresent invention. It should be understood, however, that the inventionis not limited to the specific details of the examples.

EXAMPLES The reactor used in work was a cylindrical vessel having acapacity of about7l liters constructed of one- /eighth inch aluminum (42cm. inside diameter and 57 cm. high). The walls of this reactor wereheated with 1 band heaters equipped with a 3-way switch which perwaspreferred.

Formaldehyde gas was conducted into the reactor through heated linesfrom a separate vessel where it was generated as needed by heating asuspension of between about 30 to percent by weight (unless otherwiseindicated) of paraformaldehyde in mineral oil. The reactor was furtherequipped with another line through which other gases such as air may beadmitted when and as desired. The rate of flow of formaldehyde wascontrolled by regulating the temperature of the mineral oil between and140C.

Unless otherwise indicated, all samples were tested wrinkle recoveryangle in accordance with the test methods described in AATCC 66-1959T.For Elmendorf Tearing Strength, test methods are in accordance with ASTMD-l424-59 and for Stoll Flex Abrasion Resistance, the test. methods arein accordance with ASTM-D-61T (using head and tension loads of k andEXAMPLE 1 Samples of 100 percent cotton twill fabric (112 X 50thread),were padded with aqueous solutions containing from 0 to 20percent urea and 10 percent (solids).urethane latex E-502 (WyandotteChemical Corporation) to give various add-ons. The impregnated sampleswere each dried to a moisture content of about 7 percent, exposed to agaseous formaldehyde vapor atmosphere for 2 minutesat C. and post-heatedin air for 5 minutes at 150C. Unless otherwise indicated, fabric samplesin allof the examples were post-heated immediately after exposure to thegaseous formaldehyde atmosphere. i

As shown in Table 1, fabric properties were considerably improved whenpadded with a 1 percent ureacontaining solution (about 2.6 percentmonomer addon calculated as the total add-on, Table 1, minus the add-onvalue of polymeric additive for 0 percent urea, i.e., 4.1 weightpercent) as compared with the 0 percent urea-containing solution. Theseimproved properties were generally maintained or improved with each ofthe aqueous solutions having increased urea concentrations.

Table 1 indicates that as little as 1 percent urea in the aqueoussolution imparts good durable press properties tocotton fabrics in thepresent process. These results are to be contrasted with conventionalcatalyzed durable press processes in which aqueous solution concen-TABLE I Tensile properties Wrinkle recovery angle Tearing Stoll WarpFill (degrees) strength fiex Urea concen- Add- (Elmendorf abra- Work-Exten- Work- Extentration in on, Dry Wet units) sion tosion at Breakingtosion at Breaking Bending impregnating perwarp rupture reek, strengthrupture break, strength strength solution cent Warp Fill Warp Fill WarpFill (cycles) (in.-lb.) percent (lb (in.-1b.) percent (lb (0111. 4.1 119108 136 122 164.8 108. 8 933 35. 6 18. 9 180. 5 12. 3 19. 4 71. 3 6.7146 129 157 142 218. 0 116.0 1, 175 18.1 13.9 125. 5 6. 6 14. 4 48. 6 5.l 6.8 150 144 212. 5 122. 5 1,338 18. 2 13. 6 125.0 6. 5 14. 2 50. 0 5.0 7. 4 152 132 155 138 237. 5 127.0 1, 310 20. 1 14. 6 137.0 6. 7 14. 552. 3 5. 0 8. 1 155 136 156 144 213. 5 124. 2 1, 462 22. 2 14. 2 144. 06. 1 15. 2 47. 4 5. 2 10. Z 152 136 152 142 201.0 112.0 1, 465 19. 6 13.4 133.5 6. 3 15. 1 49. 5 5. 3 19. 5 154 148 169 154 129. 0 84. 8 62615.6 9. 8 137.0 4. 8 12. 6 48. 3 5. 4 23. 9 147 144 166 149 134. 3 83. 2754 19. 4 10. 7 155. 5 7. 2 13. 9 59. 7 5. 6 N.a. 74 75 73 81 169. 4 98.3 421 31. 8 13. 2 187.0 11. 8 17. 9 71. 6

Untreated control.

EXAMPLE 11 The effect of formaldehyde exposure time and the presence ofsteam on fabric properties wasstudied in this Example in which samplesof the fabric of Example I were impregnated with an aqueous solutioncontaining 10 percent urea and 10 percent (solids) urethane latex E-502,exposed to formaldehyde vapor for from 1 to 4 minutes at 120C. in thepresence or absence of any steam and then post-heated for 5 minutes at150C. The resulting fabric properties shown in Table II indicate thatsmall increases in wrinkle recovery angle and corresponding decreases intensile strength were obtained as exposure time was increased from 1 to4 minutes.

. 8 teria 9112811 090 i 19.@E LEEEPQEFEQ;

The effect of post-heating temperature is shown'in Table lll-B. Althoughtheamount of amide add-on increased with increased temperature, mostother properties did not. After 10 laundering cycles, the fabricproperties showed little change, indicating that the process of thisinvention can be operated within wide ranges of post-heating time andtemperature without significantly affecting the balance of fabricproperties. It is known that gaseous formaldehyde generated by heatingparaformaldehyde-mineral oil slurries may contain a minor amount (i.e.,less than 5 weight percent) of impurities such as water, methanol,methyl for- TABLE 11 V Tensile properties HCHO Wrinkle tii-ecovegy anglegeariggh St E Warp Fill t ees s ren I HCHO exp o r fe Addegr (Elmendoriflex Work- Exten- Work- Extenexposure time at on, Dry Wet units)abrasion t0- sion at Breaking tosion at Breaking time at 120 120 C.perwarp rupture break. strength rupture break, strength C. (min.) (min)cent Warp Fill Warp Fill Warp Fill (cycles) (in-lb.) percent (1b.)(in-lb.) percent (1b. 0 11.8 150 130 147 142 102.7 98.8 1,234 19.5 11.5147.5 0.2 14.8 51.0 0 13.7- 154 142 150 145 157.5 90.0 1,035 17.3 11.0137.0 5.8 13.4 40. 0 3 iii it? it; 1% ii $38 23% ii? iii 1%?) 2'3 3'3238 1 1310 152 142 158 145 146:8 86:0 050 1713 1110 13715 :2 14:0 44:0'2' 14.0 152 145 154 152 148.5 87.5 811 15.8 10.8 131.0 5.3 14.0 48.0 323 ii? iii iii 33% Z1 3? 5 4% iii l'i il'fi 2'3 iii 23% 4 14.3 1 57.4.Na. 74 75 73 81 150.4 9.3 421 31.8 13.2 187.0 11.8 17.9 71.0

Untreated control. W WWW V V M H VY ;W V v 7 EXAMPLE lll foruse incatalyticallyeffective amounts in durable press processes usingformaldehyde. However, the Samples: the fabilc of Exarilgle I which were1m small amount of formic acid which could (depending pregnated w1thsolutions containing percent urea upon the, g purity) be present in theprocess f the and percent (s dfQglreth lane latex E302, drleg :0 presentinvention is so small as to 5515451551551 to a moisture content 0 apercent 3 expose o cause any significant change in the balance ofproperformaldehyde .vapor for 2 mmutes i L 22 ties obtained as comparedwith those obtained when heated varying terffpelames. an nmes e acarrying out the reaction in the absence of any catalytic shown in TableIll-A 1nd1cates that although the tensile material That is the Smallamoum'of formic acid or a a J Strength remains essennauy unchanged}; thef other material normally considered a catalyst in adurawet f recoveryangles a .ble press process includingformaldehyde which could creased mpost'heated i z as compam wit a I be present inthe process ofthe'present invention is less' Sam much 1. s eat? v than a catalyticallyeffective amount and so small as to Thus, although the theoreticalmechanism is not be insufficient to cause any significant change in theclear, itappears that further condensation probably oc- 4 5 balance ofproperties obtained as compared with those curs between urea andformaldehyde during the postobtained when carrying outthe reaction inthe absence heating step and also that further bonds may be formed ofany amount of a material normally considered a catbetwe en theurea-formaldehyde resin and the cellulosic alyst. 4mm 7 A v TABLE 111-14Tensile properties I Warp Fill Wn'nkle (gecovegy Angle Ttearh: 830311 Ei. E :8

recs 5 reng X X 8D- x 11 Post heating Add- 6g w (Elmendorfabrawort'kosior; B ah W012i; $0111; B an ti t Numb r on, D et units slon3. re 'ng a re 'ng me a e perry wra rupture break, strength rupturebreak, strength washings cent Warp Fill Warp Fill Warp Fill (cyclesin.-lb.) percent (1 (in-lb.) percent (1b.)

1 8. 9 133 117 141 137 255. 0 153. 5 888 28. 0 10. 0 153. 5 5 1s. 4 54.5 1 11.0 143 122 152 140 109.5 126.8 1,054 21.0 13.4 138.5 7.3 15.0 53.11 11.9 148 134 158 151 109.3 115. 1,508 23.2 13.4 151.0 7.3 15. 2 53.0 112.0 152 138 132 149 178.0 115. 1,428 21.4 13.0 147.0 7.2 15.2 53.4 113.9 155 140 150 151 152.0 97. 1,161 11.7 114 135.0 0.1 14.8 50.2 1 13.3155 150 158 157 159.8 95. 1,080 19.3 11.8 142.0 5.3 13.8 47.2 10 8.0 138122 142 255.0 143. 558 23.9 15.5 141.5 8.4 15.4 57.2 10 9.1 140 122 150210. 5 131. 732 21.4 14.0 140.5 7.8 15.5 55.4 10 9.9 148 133 151 142193.5 124. 1,214 20.9 13.8 141.5 7.5 15.2 50.0 10 10.0 150 134 142 202.5 120. 1,210 20.9 13.2 142.5 7.8 15.4 500 10 11.8 154 135 157 144 151.0100. 1,275 17.3 12.2 133.0 5.2 14.4 45.0 10 11. 7 152 158 140 150.8 113.1,159 18. 3 12.4 134.0 59 14.0 49.7 N.a. Na. 74 75 73 81 159.4 98. 42131.8 13.2 187.0 11.8 17.9 71.8

Untreated control.

m e a @0219 388 f m ssidii 3 5998883 0 TABLE III-B f Tensile propertiesWar Fill Wrinkle Recovery Angle 'Ieerin Stoll p (degrees) strengt flexExten- I Exten- Add- (Elrn endorl abra- Workslon Workslon Post heatingNumber on, Dry Wet units) slon t tob it Breelrln toat Breekln perwraprup ure ree stren t ru ture break, etr n t temp. C.) washings cent WarpF111 Werp Fill Warp Fill (cycles) (ln.-lb.) percent (1 1).) (ln l-lb.)percent h.) 1 11.6 143 136 150 148 177.0 113.0 18.6 13.4 132.0 7. 3 l5.1 11. 5 153 140 154 147 163. 7 101. 18. l2. 4- 136. 5 6. 5 14.2 7 1 12.7 158 141 154 152 145. 7 92. 8 979 17. 4 11. 6 136. 0 5. 5 13. 2 41). 21 13. 1 159 148 153 156 134. 8 86. 8 890 16. 7 11. 0 137. 0 5. 4 13. 248. 5 11. 6 142 122 149 142 173. 0 117. 5 21. 3 14. 8 139. 5 6. 7 15.7 1. 3 10 11. 6 152 134 158 146 151. 2 97 0 19. 1 11. (i 141. 0 6.1) 15.4 58. 2 10 12. 4 150 134 153 146 152. 8 92 2 874 17. 8 12. 4 136. 5 5. 413. 6 48. 0 10 12. 6 155 138 153 149 150. 0 92. 0 1, 006 17. 2 11. 8136.0 5. 5 13.4 50.0 N.a. N.a. 74 75 73 81 169. 4 98. 3 421 31. 8 13. 2187. 0 11. 8 17. 9 71. 6 Untreated control.

. EXAMPLE IV EXAMPLE V The effects of the moisture content of the cottonfabric prior to formaldehyde treatment were studied. Samples of thecotton twill fabric of Example I were padded with a solution containing10 percent urea and 10 percent (solids) urethane latex E-502, dried andconditioned to various levels of moisture content, exposed toformaldehyde vapor for 2 minutes at 120C. and then post-heated for 5minutes at 150C. g

It is known that in at least some prior art catalytic processesincreasing the moisture content of cotton fabrics prior to treatmentwith formaldehyde vapors increases the amount of absorbed formaldehydeas well as the amount of fixed formaldehyde. In the present process,however, the amount of water in cotton fibers does not appear to be acritical parameter in determining the extent of reaction betweenformaldehyde and urea. As shown in Table IV, add-ons for all samples 35were approximately equal and all fabric samples had acceptable durablepress properties.

The effect of surface polymeric additives on wrinkle recovery angle andstrength loss was studied by impregnating samples of the fabric ofExample 1 with aqueous solutions of various commercially availablepolymeric additives with and without urea also being present in theaqueous solutions. The impregnated fabric samples were each dried at C.to a' moisture content of about 7 percent,'exposed to formaldehyde vaporfor 2 minutes at C. and post-heated for 5 minutes at 150C. Results areshown in Table V. As expected, fabrics impregnated with the. stronger(higher film modulus value) polymeric additives such as Rhoplex K -87and urethane latex P -50l generally show greater strength and lowerwrinkle recovery angles than the fabrics impregnated with the lowerstrength polymeric additives Rhoplex K-14 and urethane latex E-502.

E MBLE TABLE IV Tensile properties Warp Fill Wnnkle recovery angle TearmStoll (degrees) strengt flex Exten- Exten- Initial No. (Elmendorf abra-Werksion Worksion moisture of Dry units) sion toat Breaking toatBreaking Add-on, content, weshwarp rupture break. strength rupturebreak, 1 strength percent percent ings Warp Fill Warp F111 Warp Fill(cycles) (in-lb.) percent (1b.) (1n.-lb percent (15.) 11.3 3. 5 1 150132 152 144 179. 0 141 2 1, 886 24. 0 14. 8 145. 5 8. 2 15. 6 51. 6 11.47. 2 1 161 150 159 155 139. 8 87 5 932 15. 2 10. 6 129. 5 5. 4 13. 5 47.2 11.8 16. 0 1 158 152 167 153 135. 2 84. 0 847 16. 2 11. 0 131. 5 5. 813. 8 50. 9 11.4 3. 5 10 140 158 138 202. 0 158. 2 1, 866 27. 9 17. 5148. 0 8. 6 16. 4 57. 7 11.2 7. 2 10 158 142 164 152 163. 2 99. 8 1, 25817. 7 12. 1 131. 0 5. 5 14. 0 46. 0 11.7 16.0 10 154 169 157. 0 88. 5 1,222 16. 3 11. 8 128. 0 5. 4 14. 0 46. 1 N.a. N.a. N.a. 74 75 73 81 169.4 98. 3 421 31. 8 13. 2 187. 0 11. 8 17. 9 71. 6

Untreated control.

TABLE v Wrinkle Recovery Tensile Strength Additive Add-on Angle, W F (7:retention) (7! solids) (7r) (degrees) Dry Wet Warp Fill 2.5% RhoplexK-87" 1.8(8.3 170(296) 195(292)" 90(74)" 97(66)" 5.0% Rhoplex K-873.1(9.7) 177(296) 204(300) 89(74) 108(71) 7.5% Rhoplex K-87 4.l(ll.l)191(294) 206(303) 91(73) 100(70) 10.0% Rhoplex K-87 5.4( 12.8) (300)217(301) 94(78) 95(77) 2.5% Rhoplex K-l4 1.0(7.6) l9l(265) 188(258)79(71) 91(58) 5.0% Rhoplex K-l4 2.5(86) 206(280) 218(261) 83(68) WrinkleRecovery Tensile Strength Additive Add-on Angle. W F (7: retention) ("/1solids) ('72. (degrees) Dry Wet Warp Fill 7.5% Rhoplcx K-l4 2.9(9.4)222(280) 217(283) 75(68) 83(59) 10.0% Rhoplex K-l4 4.3(! 1.6) 225(274)235(279) 77(69) 79(66) 2.57: U. L. P'SOI 0.9(83) lli4(284) 204(274)94(74) l()l(74) 5.09? U. L. P-SOl 2.4( 10.2) 205(288) 224(28I) 94(8l)lUl(75) 7.59? U. L. P-SOl 3.8(l2.0) 204(293) 238(296) 98(82) 98(8l) 100%U. L. P-50] 5.()( 13.4) 222(288) 254(298) 96(85) 98(78) 2.5% U. L.E-502" 2.1(64) 206(268) 222(264) 89(72) 93(76) 5.07: U. L. E-5023.2(8.4) 214(285) 232(286) 78(77) 89(66) 7.571 U. L. E-SOZ 4.4(l().3)235(298) 259(293) 81(72) 94(66) 10.0% U. L. E-502 5.2( 12.5) 227(302)263(305) 82(7l) 89(69) Control n.a. 149 154 I 100 a an acrylic resinavailable from the Rohm and Haas Co. b-an acrylic emulsion availablefrom the Rohm and Haas Co.

0- Urethane Latex P-50l available from the Wyandotte Chemical Corp. dUrethane Latex E502 available from the Wyandotte Chemical Corp.

e-FlgUICS in parenthesis denote values for fabric treated in thepresence of urea based on the weight of pad bath).

to the foamaldehyde vapor and the post-heating step were consideredinthis example.

Samples of the fabric of Example I were padded with an aqueous solutioncontaining 10 weight percent urea and 10 weight precent urethanelatexE-SOZ. The impregnated sampleswere dried to a moisture content ofAngles and Durable Press Ratings as compared with the untreated control,both show unacceptable properties for commercial durable pressmaterials. Both samples also show properties substantially less than thesamples of Table Vl-A. In addition, this data shows that post-heatingonly moderately improves the durable about 7'percent, pressed andexposed to a 100 percent Press Properties Washed mPl Time betweenexposure to gaseous formaldehyde and post-heating,

TABLE Vl-A.

Wrinkle Recovery Angles, (W Durable Press Ratings F). degrees hours DryWet 0 292 297 4.1 l 293 310 4.1 2. 288 314 4.1 4 286 327 4.1 6 285 3014.0 24 274 316] 4.0 72 309 315 4.0 144 299 330 4.0, Untreated Control149 I54 I [,5

formaldehyde vapor atmosphere for 2 minutes at TABLE VLB 120C. Thesamples were held for varying times and I then post-heated in air at150C. for 5 minutes. The re- Sample Wrinkle Recovery Angle Durable Presssuits are shown in Table VI-A. 83+ grees ll 'leatltngs The resultsobtained indicate that the impregnated g fabrics were not affected bydelaying the post-heating 1 230 :2? a step since the resultingproperties wereessentially the Untreamg Comm] fig 1 same (and within thelimits of experimental error) whether the fabric was post-heatedimmediately or after 6 days.

Samples of the same fabrics as above were impregnated, dried andexposed'to gaseous'formaldehyde in the same manner as above and werewashed immediately after exposure to the formaldehyde vapors. Sam- 7EXAMPLE'VH The interaction of the impregnation of the amide, im-

ple l was not post-heated. Sample ll was post-heated for pregnation ofthe polymeric additive and contact with 5 minutes at C. and washedagain.

The results obtained are shown in Table VI-B. Although both samples showhigher Wrinkle Recovery gaseous formaldehyde was considered .in-thisexample. The varying treatments applied to the fabric samples as well asthe results obtained are shown in Table VI].

TABLE vu Pretreatment Posltreatment Formaldehyde Wrinkle RecoveryTensile Strength Exposure Angle (degrees) (/1 retention) Time'(min) DryWet None None I 145 172 97 5 142 164 88 ll) l 33 I66 86 15 I42 I64 99 20I43 I70 95 1071 E-SOZ" None I90 I67 88 l 236 260 85 235 259 89 l() 246266 86 263 284 83 252 280 82 10% Urea None 1 267 253 65 2 262 248 70 3251 243 72 4 270 250 76 10 7r Urea 1071 E-502 l 298 285 50 2 288 277 673 291 279 69 4 294 280 62 10% Urea None 1 280 289 71 10% E-502 2 296 30270 3 307 308 69 4 303 310 66 All fabrics posthealed for 5 min at 150C. IPercent solids in aqueous solutions As shown therein, samples of thefabric of Example I exposed to gaseous formaldehyde for l to 20 minutesat 120C. without prior impregnation with the mono- Y mer or the surfacepolymeric additive exhibited noincreases in wrinkle recovery angles(hereinafter WRAs) even after 20 minutes of treatment. These fabrics,however, sufferedtensile strength losses of l to 14 percentrespectively. I

Fabrics padded with an aqueous solution containing 10 percent (solids)urethane latex E-502 exposed to formaldehyde vapor for 5 to 20 minutesand postheated for 5 minutes at 150C., exhibited moderate degrees ofrecovery angles (235 4 263dry and 259 280 wet), probably indicating achemical interaction between the urethane latex, formaldehyde and cellulose. Although the dry WRAs proved tobe nondurable to laundering, thewet WRAs were unchanged after 10 laundering cycles. The loss in tensilestrength exhibited by these samples was between 1 l and 18 percent. Y

In another part of the experiment, fabrics were padded with a 10 percenturea solution, dried to a moisture content of about 7 percent, exposedto gaseous formaldehyde for l to 4 minutes at l20C.,-and post-heated for5 minutes at 150C. These fabrics also showed only moderate WRAs buthigher strength losses in fabrics treated with formaldehyde in thepresence of the urethane latex alone.

To study the effect of applying the urethane latex to fabrics that hadbeen treated with the urea formaldehyde system in the absence of-apolymeric additive, fabrics from the previous experiment were re-paddedwith an aqueous solution containing 10 percent solid urethane latexE-502, dried and then cured for 5 minutes at 150C. As shown in TableVlll, the dry and wet WRAs increased by'about each while the tensilestrengths decreased 3 to 10 percent. After 10 laundering cycles, mostproperties showed little change.

The principles, preferred embodiments and modes of operation of thepresent invention have been described in the foregoing specification.The invention which is intended to be protected herein, however, is notto be construed as limited to the particular forms disclosed,

since these are to be regarded as illustrative rather than restrictive.Variations and changesmay be made by those skilled in the art withoutdeparting from the spirit of the invention. I

What is claimed is: I 1

1. Anon-catalytic process for improving the dimensional stability,wrinkle resistance, smooth drying characteristics and total shaperetentivity of a cellulose fiber-containing fabric which comprises:

a. applying to a cellulose fiber-containing fabric a catalyst-freeaqueous solution of a monomeric amide compound which has at least oneactive hydrogen and reacts with formaldehyde;

b. exposing the impregnated fabric to an atmosphere containingformaldehyde vapors in the essential absence of an acidic catalyst untila crease-proofing amount of an at least partially polymerizedcondensateof the monomeric amide compound and formaldehydein ubstatially water in soluble form is affixed on said fabric withiaufeffectingany sub stantial amount of cross-linking with the cellulose fiber; and vsphere in the essential absence of an acidic catalyst at a temperatureof from about C. to about C. for from about 1 to about 20 minutes tofurther polymerize and cross-link the fabric.

2. The process of claim 1 wherein said amide is urea and further whereinsaid fabric is impregnated with the aqueous solution of urea so as toproduce a dry add-on of en bo t 7 395 2 FBU21LW E. h fabric. 7

3. The process of claim 1 wherein said impregnated fabric is formed intoa garment prior to exposure to the formaldehyde vapors.

4. The process of claim 1 wherein said impregnated fabric is dried to amoisture'content of from about 2 to about 100 percent by weight of thedry cellulosic fabric material prior to exposure to the formaldehydevaporcontaining atmosphere.

5. A non-catalytic process for improving the dimensional stability,wrinkle resistance, smooth'drying charpost-heating said fabric in aninert gaseous atmoher-containing fabric which comprises:

a. applying to a cellulose fiber-containing fabrica catalyst-freeaqueous solution .of a monomeric amide compound which has at leastone'active hydrogen and reacts with formaldehyde and a polymericfilm-forming additive so as to produce an impregnated fabric havingtadry add-onvof between about 0.5 and 25 percent by weight of the fabricof the said monomeric amide compound;

b. drying said impregnated fabric;

c. forming said'impregnated fabric into a garment;

d. exposing the impregnated garment to an atmosphere containingformaldehyde vapors in the essential absence of an acidic catalyst at atemperature of from about 100C. to about 160C. for from about 0.1 toabout 60 minutes until a creaseproofing amount of an at least partiallypolymerized condensate of the monomeric amide compound and formaldehydein substantially waterinsoluble form is affixed on said fabric withouteffecting any substantial amount of cross-linking wit the cellulosefiber;

e. post-heating said exposed garment in an inert gaseous atmosphere inthe essential absence of an acidic catalyst at a temperature of fromabout .l00C. to about 180C. for from about 1 to about 20 minutes tofurther polymerize and cross-link the from about 3 to about 65 percentbyweightof the dry cellulose fiber-containing fabric prior to exposureto 16 the formaldehyde vapor-containing atmosphere.

8. The non-catalytic process of claim 7 wherein said impregnated fabricis exposed to the formaldehyde vapors for a time of from about 0.5 toabout 20 minutes.

9. A non-catalytic process for improving the dimensional stability,wrinkle resistance, smooth drying characteristics and total shaperetentivity of a cellulose fiher-containing fabric which consistsessentially of the following sequential steps: r

a. applying to the cellulose fiber-containing fabric a catalyst-freeaqueous solution containing from about 5 to about 15 percent by weightof the solution of urea and from about 5 to about 15 percent of afilm-forming polymeric additive;

b. drying the impregnated fabric to a moisture content of from'about 5to about 15 percent by weight of the dry cellulose fiber-coptainingfabric;

c. exposing the dried, impregnated fabric to a vapor phase atmosphereconsisting essentially of formaldehyde vapors in an uncatalyzed reactionzone 7 maintained at a temperature of from about l05C.,

d. immediately thereafter post-heatingsaid fabric in an inert gaseousatmosphere inthe essential absence of an acidic catalyst at atemperature of from about C. to about C. for a time of from about 3 toabout 10' minutes to further polymerize and cross-link said fabric.

2. The process of claim 1 wherein said amide is urea and further whereinsaid fabric is impregnated with the aqueous solution of urea so as toproduce a dry add-on of between about 0.5 and 25 percent by weight ofthe fabric.
 3. The process of claim 1 wherein said impregnated fabric isformed into a garment prior to exposure to the formaldehyde vapors. 4.The process of claim 1 wherein said impregnated fabric is dried to amoisture content of from about 2 to about 100 percent by weight of thedry cellulosic fabric material prior to exposure to the formaldehydevapor-containing atmosphere.
 5. A non-catalytic process for improvingthe dimensional stability, wrinkle resistance, smooth dryingcharacteristics and total shape retentivity of a cellulosefiber-containing fabric which comprises: a. applying to a cellulosefiber-containing fabric a catalyst-free aqueous solution of a monomericamide compound which has at least one active hydrogen and reacts withformaldehyde and a polymeric film-forming additive so as to produce animpregnated fabric having a dry add-on of between about 0.5 and 25percent by weight of the fabric of the said monomeric amide compound; b.drying said impregnated fabric; c. forming said impregnated fabric intoa garment; d. exposing the impregnated garment to an atmospherecontaining formaldehyde vapors in the essential absence of an acidiccatalyst at a temperature of from about 100*C. to about 160*C. for fromabout 0.1 to about 60 minutes until a crease-proofing amount of an atleast partially polymerized condensate of the monomeric amide compoundand formaldehyde in substantially water-insoluble form is affixed onsaid fabric without effecting any substantial amount of cross-linkingwith the cellulose fiber; e. post-heating said exposed garment in aninert gaseous atmosphere in the essential absence of an acidic catalystat a temperature of from about 100*C. to about 180*C. for from about 1to about 20 minutes to further polymerize and cross-link the fabric. 6.The non-catalytic process of claim 5 wherein said amide is urea.
 7. Thenon-catalytic process of claim 6 wherein said impregnated fabric isdried to a moisture content of from about 3 to about 65 percent byweight of the dry cellulose fiber-containing fabric prior to exposure tothe formaldehyde vapor-containing atmosphere.
 8. The non-catalyticprocess of claim 7 wherein said impregnated fabric is exposed to theformaldehyde vapors for a time of from about 0.5 to about 20 minutes. 9.A non-catalytic process for improving the dimensional stability, wrinkleresistance, smooth drying characteristics and total shape retentivity ofa cellulose fiber-containing fabric which consists essentially of thefollowing sequential steps: a. applying to the cellulosefiber-containing fabric a catalyst-free aqueous solution containing fromabout 5 to about 15 percent by weight of the solution of urea and fromabout 5 to about 15 percent of a film-forming polymeric additive; b.drying the impregnated fabric to a moisture content of from about 5 toabout 15 percent by weight of the dry cellulose fiber-containing fabric;c. exposing the dried, impregnated fabric to a vapor phase atmosphereconsisting essentially of formaldehyde vapors in an uncatalyzed reactionzone maintained at a temperature of from about 105*C. to about 120*C.for a time of from about 1 to about 5 minutes, until a crease-proofingamount of an at least partially polymerized amide-formaldehydecondensate in substantially water-insoluble form is affixed on saidfabric without any substantial cross-linking with the cellulose fiber;and d. immediately thereafter post-heating said fabric in an inertgaseous atmosphere in the essentIal absence of an acidic catalyst at atemperature of from about 140*C. to about 160*C. for a time of fromabout 3 to about 10 minutes to further polymerize and cross-link saidfabric.